TMS - Laboratory

 

Description

Transcranial magnetic field stimulation (TMS) is an innovative technology with promising applications in the diagnosis and treatment of various neurological and mental illnesses such as depression, Parkinson's disease and schizophrenia. The complete TMS system installed in the laboratory enables computer-controlled positioning with integrated movement compensation and thus stimulation of the patient or test person with (sub)millimeter precision. Neuronavigation, real-time activity prediction and simultaneous monitoring of physiological parameters (e.g. EEG) complete the system, which consists of a total of 4 subsystems:

 
 

Example application

 
TU Ilmenau
TMS system:

Company and model: Magstim, Rapid2 With the help of this TMS system, different stimulation paradigms can be realized (single pulses or repetitive mode), whereby primarily the frequency and the number of stimulation pulses are varied (stimulation with up to 100Hz possible). The strength of the magnetic field can be varied as a percentage (0%-100%) and depends on the stimulation coil used (between 0.7-3.5T).

 
TU Ilmenau
Robot system:

Company and model: Adept, Viper robot s850 This robot is a six-axis robot which, within its working range, is able to approach any position quickly, with high precision (submillimeter) and reproducibly. The robot is used to position the stimulation coil.

 
TU Ilmenau
EEG system:

Company and model: ANT, asa-lab This is a system for measuring the electroencephalogram with a sampling frequency of up to 2048 HZ and up to 256 channels. It can be used to measure the EEG in parallel with the stimulation, allowing conclusions to be drawn about the effect of the stimulation on brain functionality.

 
Navigation system:

Company and model: ANT, Visor 3D Neuro Navigation

At the heart of this system is an infrared camera (NDI Spectra), which can calculate and track the position of markers reflecting infrared light (also with sub-millimeter accuracy). The camera system is used to determine and continuously monitor the exact position of the robot and the coils. In parallel, there are reflective markers on the patient's head, so the robot can be controlled using the software supplied so that it moves the coil to the correct position on the patient's head and tracks it when the head moves. This ensures precise stimulation.

Fields of application:

The areas of application for TMS are very diverse. It has been used successfully for years in both research and clinical practice. In general, TMS makes it possible to stimulate the brain without having to surgically insert electrodes. Diagnostics: Stimulation of the motor cortex with individual impulses leads to the triggering of motor-evoked potentials, which are then transmitted to the corresponding limb (arm, finger, leg). Many neurological diseases such as multiple sclerosis or medication/drugs influence this transmission. TMS can now be used to specifically investigate such disorders. Therapy: Repetitive TMS can stimulate or inhibit the activity of certain areas of the brain. This is used, for example, to treat depression and schizophrenia in longer therapy sessions.

Research: Peripheral magnetic stimulation is performed on the median nerve of the right arm and multi-channel EEG signals are recorded in parallel to measure so-called somatosensory evoked potentials (SEPs) in the brain of the test subjects. In the area of transcranial stimulation using TMS, the influence of the subject's position on the effectiveness of the magnetic stimulation is analyzed in more detail.